Rapidly progressive glomerulonephritis overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Rapidly progressive glomerulonephritis (RPGN) is a syndrome of the kidney that, if left untreated, rapidly progresses into acute renal failure and death within months. In 50% of cases, RPGN is associated with an underlying disease such as Goodpasture syndrome, systemic lupus erythematosus, or Wegener granulomatosis; the remaining cases are idiopathic. Regardless of the underlying cause, RPGN involves severe injury to the kidney's glomeruli, with greater than 50% of the glomeruli containing characteristic crescent-shaped scars. Because of this microscopic feature, RPGN is also called crescentic glomerulonephritis.
Patients with RPGN have blood in the urine (hematuria), urinary protein (proteinuria), and occasionally high blood pressure (hypertension) and edema. The clinical picture is consistent with nephritic syndrome, although the degree of proteinuria may occasionally exceed 3 g/24 hr, a range associated with nephrotic syndrome. Untreated disease may progress to decreased urinary volume (oliguria), which is associated with poor kidney function.
RPGN is classified into three types, all of which involve immune-mediated damage to the glomeruli. In type I RPGN, which accounts for approximately 20% of RPGN cases, injury is caused by antibodies directed against the glomerular basement membrane. Type II RPGN accounts for roughly 25% of RPGN cases and is characterized by the deposition of immune complexes in the glomerulus. The remainder of RPGN cases are type III, or pauci-immune RPGN, which features antibodies directed against neutrophils (anti-neutrophil cytoplasmic antibodies, ANCA).
Treatment depends on the underlying disease process. For example, plasmapheresis, corticosteroids, and cytotoxic drugs may promote recovery in Goodpasture syndrome, a cause of type I RPGN. Despite even early treatment, however, many patients with RPGN may ultimately require dialysis and possibly renal transplant.
Historical Perspective
Classification
Pathophysiology
Causes
Differentiating rapildy progressive glomerulonephritis from Other Diseases
The various types of glomerulonephritides should be differentiated from each other based on associations, presence of pitting edema, hemeturia, hypertension, hemoptysis, oliguria, peri-orbital edema, hyperlipidemia, type of antibodies, light and electron microscopic features.
Epidemiology and Demographics
Risk Factors
Screening
There is insufficient evidence to recommend routine screening for rapidly progressive glomerulonephritis.
Natural History, Complications, and Prognosis
Diagnosis
Diagnostic Study of Choice
Determination of ANCAs can aid in the diagnosis, but positivity is not conclusive and negative ANCAs are not sufficient to reject the diagnosis. Cytoplasmic staining ANCAs that react with the enzyme proteinase 3 (cANCA) in neutrophils (a type of white blood cell) are associated with Granulomatosis with polyangiitis. If the patient has renal failure or cutaneous vasculitis, these are the most logical organs to obtain a biopsy from. Rarely, thoracoscopic lung biopsy is required.
History and Symptoms
Physical Examination
Laboratory Findings
Electrocardiogram
X-ray
Echocardiography and Ultrasound
CT scan
MRI
Other Imaging Findings
Other Diagnostic Studies
Treatment
Medical Therapy
Treatment of RPGN depends on the underlying disease process. For example, plasmapheresis, corticosteroids, and cytotoxic drugs may promote recovery in Goodpasture syndrome, a cause of type I RPGN. Despite even early treatment, however, many patients with RPGN may ultimately require dialysis and possibly renal transplant.
Surgery
Surgery is not the first-line treatment option for patients with rapidly progressive glomerulonephritis. Renal transplantation is usually reserved for patients who present with undetectable circulating anti-glomerular basement antibodies in serum for 12 months and at least 6 months after stopping the use of cytotoxic agents.
Primary Prevention
There are no established measures for the primary prevention of Rapidly progressive glomerulonephritis.
Secondary Prevention
There are no established measures for the secondary prevention of Rapidly progressive glomerulonephritis.